The object of these studies is to improve our understanding of the relationship between allergens in house dust and the allergic diseases, asthma and rhinitis. Of the 8 million asthmatic patients in the United States, between 40% and 60% will give position skin tests with hosue dust extract, yet the nature of the allergens in floor dust and their role in asthma is poorly understood. The first objective is to purify a 'major' allergen from the dust mite. Dermatophagoides farinae. This allergen will be used to develop radioimmunoassays both to measure antibodies in serum and to measure quantities of the allergen. These assays will be carried out in parallel with similar assays using the D.pteronyssinus allergen. antigen p1, which we have previously identified. Assays for D.farinae allergen will be used: (i) to check our previous observation that the form in which mite allergens accumulate, become airborne and are inhaled is as fecal pellets of approximately 20 um in diameter, and (ii) to measure quantities of allergen in dust from patients' houses. Dust from patients' houses will also be examined for numbers of mites and mite species. In order to allow use of allergen assays on a large number of samples, we intend to develop monoclonal antibody-based assays to measure a representative allergen(s) of the two species. These two species (D. pteronyssinus and D.farinae) are dominant in at least 95% of the houses seen in Virginia. Patients will be studied in order to relate skin test results to serum ab measurements and also to study the relationship between dust mite allergen exposure and allergic disease. The first priority is to establish what proportion of house dust allergic patients are allergic to mites (at least 75% of patients seen so far). Secondly, we will measure mite allergens in patients' houses and relate these levels to those in control houses, hospitals and public places. These studies are intended to establish objective criteria for the assessment of house dust sensitivity and of mite allergen levels in houses. We believe that these measurements will help both with the diagnosis and the management of rhinitis and asthma.